Semi-Blind Channel Estimation Based on Signal Subspace Tracking for MIMO-OFDM System

In order to solve the problems of high computational complexity, large amount of computing which semi-blind channel estimation algorithm based on subspace has for MIMO-OFDM system, the MIMO-OFDM semi-blind channel estimation algorithm based on the projection approximation subspace tracking (PAST) is proposed. The decomposition of signal subspace is equivalent to solving unconstrained optimization problem. The unconstrained optimization problem is simplified into exponent-weighted least squares problem by introducing PAST method. To ensure tracking signal subspace accurately and signal orthogonal in each iteration process, the orthogonal weighted matrix is introduced. Theoretical analysis and simulation results show that the improved algorithm accelerates the convergence rate and reduces the complexity of computing while maintains the performance unchanged compared to the original algorithm.